The present invention relates to a hydraulic clutch having a modulation mechanism and applicable to industrial machines, construction machines, ships and others.
A modulation mechanism has been used for slowly engaging a hydraulic clutch. Conventionally, a valve mechanism has been used as the modulation mechanism, and a few types of the modulation mechanisms have employed spring mechanisms. However, in the former, a valve such as pressure increasing type, accumulator type, variable restrictor type, selective restrictor type or others is arranged in an external hydraulic line connected to the clutch, which complicates constructions and causes increase of cost. In the latter, such construction is employed that a belleville spring is arranged in the clutch, or that a friction plate is shaped conical and has elasticity, or other. However, in any of the constructions, since elastical deformation is limited, and enough deformation is hard to obtain, desirable modulation characteristic is hard to obtain. Also, wear changes the characteristic.
Accordingly it is an object of the invention to provide an improved hydrauric clutch, overcoming the above-noted disadvantages, wherein a modulation mechanism of accumlation type is arranged in a hydraulic piston for pushing and pressing friction plates.
Other and further objects, features and advantages of the invention will appear more fully from the following description of the preferred embodiments of the invention.